Shock absorber



- 42 sheets-sheet 1 E. F. ROSSMAN El AL SHOCK ABsoRBER Filed Aug. 23, 1957 Feb. 2s, 1939.

5J ATTORNEYS INVENTORS Feb.2s,1939. E. F. RQSSMAN Ef 2,148,839

sHocK ABsoRBER Filed Aug. 23, 1957 l 2 sheets-sheet 2 l fxylz ATTORN EYS Patented 28, 1939 PATENT OFFICE snoei; insomma Edwin F. Rossman and Frederick D. Funston,

Dayton, Ohio, assignors to General Motors Corporation, Detroit, Mich., a corporation of Delaware Application August 23,

9 Claims.

'Ihis invention relates to improvements in hydraulic shock absorbers.

It is among the objects of the, present invention to provide a hydraulic shock absorber, particu'- larly of the direct acting type, capable of controlling both the approaching and separating movel ments of two relatively movable members.

Another object of the present invention is to provide a hydraulic shock absorber with adjustable fluid ow controlling means whereby the re sisting effect of the shock absorber may be varied at will.

A still further object of the present invention is to provide a hydraulic shock absorber of the direct acting type, having uid iow controlling means adapted to be adjusted to vary its restriction to fluid flow by rotation of the shock absorber piston within its cylinder.

Further objects and advantages of the present 20 invention will be apparent from the following description, reference being had to the accompanying drawings wherein a preferred embodiment of one form of the invention is clearly shown.

In the drawings:

Fig. 1 is a fragmentary side view of a vehicle chassis, withwheels removed, showing the shock absorber of the present invention applied thereto.

Fig. 2 is a fragmentary view of the lower end of the shock absorber taken substantially in the direction of the arrow 2 of Fig. 3.

Fig. 3 is a fragmentary longitudinal sectional view of the shock absorber taken along the line 3-3 of Fig. 2.

Fig. 4 isa fragmentary side view of the uid flow controlling means associated with the shock absorber piston, the view being taken substantially in the direction of the arrow 4 of Fig. 3.

Figs. 5to 12 inclusive are views showing various eleme-nts of the shock absorber, the Fig. 5 illustrating the star-shaped resilient element of one of the fluid flow control devices of the piston:

s The Figure 6 showing one of the fluid flow control devices; 1

The Figure '7 being piston block itself;

The Fig. 8 a plan view of the retainer element of thepiston, this view being partially sectioned more clearly to illustrate the side opening thereof;

The Fig. 9 being an inverted plan view of the retainer element;

The Fig. 10 a plan view of the sleeve valve rotatably carried by the retainer of the piston;

The Fig. l1 a plan viewL of the detent or locking element; and

The Fig. 12 a. detailed plan view of the lower 'a detail plan view bf the 1937, Serial No. 160,442

(Cl. 18S-88) cylinder head with its fluid ow controlling means, this view being taken substantially in the direction of the arrow l2 of Fig. 3.

As has been stated, the shock absorber is adapted to control approachingand separating movements of two relatively movable members, in this instance the frame 20 of a motor vehicle and the axle 2|.

The shock absorber comprises two concentrically spaced` tubular members (22, the inner one, and 23, the outer one) which form a working cylinder 24 and a surrounding fluid reservoir 25. At the lower end of the outer tubular member 23 there is provided a closure member 26 having a -mounting ring 21 secured thereto, this mounting ring being adapted to be secured to the vehicle axle 2| in any suitable manner. At the lower end of the tubular member 22 there is provided a cylinder head member 28 which rests within the closure member 26 at the point 29, thus properly centering the tubular member 22 within the tubular member 23. The upper ends of the tubular members 22 and 23 are provided with a closure head member similar in construction to the shock absorber illustrated and described in Patent 2,036,955, issued to J. E. Padgett, April '1, 1936, and no detailed description will be given inasmuch as this portion of the shock absorber does not enter'into the features of the present invention. Like the patent just referred to, this shock absorber is provided with a dust cover, in the form of a tubular member 30, secured tothe upper mounting ring 3| in any suitable manner, which mounting ring is attached to the vehicle frame 2li as shown in Fig. 1.

One end of the piston rod 4|) is secured to the mounting ring 3|. This rod 40 is slidably supported within the upper closure member and extends concentrically into the Working cylinder 24. The lower end of the rod 40, or more specifically the end that extends into the cylinder 24, has a reduced diameter portion 4| presenting the annular shoulder 42. The end of this reduced diameter portion 4| is screw-threaded as at 43. A backing disc 44 isl centrally apertured to lit upon the portion 4| of the piston rod and engages with the shoulder 42 thereon. irectly beneath this backing disc 44 there is provided the star-shaped resilient disc member 45 L shown in plan view in Fig. 5, this disc being centrally apertured as at 46 to receive the portion 4| of the shaft 40.

'I'he'one fluid flow control device-41 of the piston is placed upon the shaft portion 4| directly beneath the resilient disc 45. As shown in Fig. 6, this fluid flow control device is centrally apertured as at 48 to receive the shaft portion men-y tioned. A c-shaped slot 49 is provided in the disc` 41 concentric to the central opening 48. This fluid ow control device is exible, being made up of any suitable thickness of flat spring material. Next the main piston block 50 is positioned on the piston rod portion 4|, this block being shown in plan view in the Fig. 7. Like the discs 45 and 41, it has a central aperture 6| to receive said shaft portion. On the upper surface of the piston, or that surface in juxtaposition to the flexible disc-valve 41, there are provided two annular grooves 52 and 53 concentric to the central aperture 5|. These grooves provide three annular ridges 54, 55 and 56, all lying in the same plane. A series of openings 51 pass through the piston block and provide communication between the annular groove 52 in the upper surface of the piston block and the recess 60 in the lower end of the piston block. As shown in Fig. 7, six of such passages are provided; however, more or less of them may be used in accordance with the requirements.

A series of similar passages 6| provided communication between the recess 60 in the lower end of the piston'block and the annular groove 53 in the upper surface of said block.

From the aforegoing description and referring to Fig. 3 in particular, it may be seen that the iiexible disc-valve 41 maintains passages 5 1 constantly open, for when said disc-valve is mounted upon the piston rod, the C-shaped slot 49 therein is constantly in alignment with the annular groove 52 from which the through passages 51 lead. It will also be noted that the outer peripheral portion of this disc-valve 41 is normally,

yieldably urged upon the annular ridges 55 and 56 of the piston block by the resilient disc-member 45, thus said resilient disc-valve 41 normally, yieldably closesthe outer annular groove 53 in the piston block from which through passages 6| lead.

To hold the piston block 50 so that the backing collar or disc 44 always engages shoulder 42 and the resilient disc 45 and iiexible valve member 41 are tightly clamped between said backing disc or collar 44 and the annular ridge 54 of piston block 50, there is provided a retainer member or collar 10 which threadedly engages the portion 43 of the piston rod. 'Ihis retainer collar is screwed upon the shaft so that its upper surface clamps tightly against the lower surface of the piston block 50, or more specifically the innern bottom surface of the recess 80 in said piston block. The end surface of said retainer element 10 engaging the piston block has an annular groove 1| provided thereon. 'I'his annular groove aligns and is in constant communication with the piston passages 51 which, as has been mentioned heretofore, are constantly maintained open by the exvible iiuid flow control device or disc-valve 41 of the piston. Y

The outer annular wall defining recess 1| has a side opening 12 providing communication between the annular groove 1| and the outer part of the retainer 10 which lies within the confines of the recessed portion 60 of the piston, as shown in Fig. 3. The end of the retainer 10 opposite that engaging the piston block has a plurality of equally spaced and radially arranged ridges 80, shown in Figs. 3 and 9.

Another fluid iiow control device is provided in the piston, this one being in the form of a sleeve 85 rotatably carried on the retainer element 10. A recess in the lower end of the sleeve the retainer co1lar 10 by the outwardly extending flange 81 at its lower end` The upper edge of the sleeve element 85 extends over a portion ofthe side opening 12 in the outer wall of the retainer element 10. Extending overa portion of the opening 12, the sleeve member 85 will naturally restrict the fluid ow therefrom. In order to provide for a variable restriction as the sleeve element 85 is rotated from the retainer element 10, the upper edge of said sleeve element extending over a portion of the opening 12 is sloped, as shown at 90 in the Fig. 4 in particular, the deepest portion oi'v this slope being indicated by the reference numeral 9| in Figs 4 and 10.

In order that the sleeve member 85 may not, oi' its own accord, rotate upon the retainer element 10 and vary its restriction to uld ow from the opening 12, applicant has provided a yieldable locking member or detent 92, ring-shaped as shown in Fig. 11 having an outwardly extending tongue portion 93. This ring-shaped detent fits over a circular projection 95 at the bottom end of the retainer element 10 and rests upon an abutment ring 96 secured in the bottom recessed portion of the sleeve member 85. The tongue 93 of this detent extends through a side opening 91 in the sleeve member 85. The dents or humps 98 in the detent, on diametrically opposite sides thereof, yieldably, lockingly engage notches in the retainer element 10. Thus it may be seen that this detent 9?. yieldably holds the rotatable sleeve member in any one of a plurality of adjusted positions upon the retainer 10. The sloping upper edge of the sleeve member 85 provides a variable dam in front of the side opening 12 in the retainer 10 to restrict the fluid iiow therefrom. The ring-shaped detent 92 clamped between the retainer 10 and the abutment washer 96 in the sleeve 85 is slightly dished so that normally it is tensioned, exerting a pressure upon the sleeve 85 to urge it so that its shoulder 86 constantly rides upon the shoulder provided bythe ange 81 on the retainer 10. Due to this detent the sleeve 85 is not free to rotate on the retainer 10, but is yieldably held in adjusted position, and when rotated the humpsor dents 98 of the detent will be moved from notch to notch provided by the annular row of radial ridges 80.

As has been said before, the lower end of the cylinder (tubular member 22) is provided with a head member 28. This head member has a port |00 providing communication between the lower displacement chamber 99 and the uid reservoir `25. An annular ridge |0|, extending upwardly into the cylinder, provides a valve-seat about this port |00. A valve device is provided for controlling the iiuid ow through the port |00 in opposite directions. This valve device comprises a disc-valve |02, having a central aperture ln which a tubular member |03 is slidably carried. The upper end of this tubular. member has an outwardly extending iiange |04 -which normally rests upon the upper surface of the disc-valve |02, as shown in Fig. 3. The lower end of the tubular valve member |09 is closed as at |05. Two side openings |06-and |01 are provided in the wall of the tubular valve member |03. Adjacent its closed end a retainer collar |08 is provided, this collar forming an abutmentfor one endof the spring |09, the opposite end of said spring engaging the head member 28( This spring pressing upon the collar l| 08 normally yieldably urges the disc-valve |02 upon the valve seat |0| Masse surrounding the port I 06. Another valve I I0 having a tubular body portion and an enlarged head portion; is slidably mounted on the tubular valve |03. It has an inner annular groove in constant communication with the side opening |06 in the tubular valve |03. This valve member |I0 is yieldably urged into engagement with the bottom surface of the disc-valve |02 by a springv I I3 interposed between the valve ||0 and the abutment collar |08.

As shown in Fig. 2, a series of equally spaced marks |25 are provided in the outer surface of the tubular member 23. These marks are spaced to correspond to the spacing of the radial notches 60 on the bottom surface' of the retainer mem' ber 10. A central V-shaped marker |26 is provided in the row of markings |26, and on one side of this V-shaped marker |26 there appears the word Firm and on the opposite side the word Soft. These are indications as to the adjustment of the sleeve valve 65 on the retainer 10, or more particularly asto the degree or amount of restriction offered by the sleeve valve 86 to the fluid flow through the side opening 12 in said retainer. A V-shaped notch |21 in the dust cover 30 cooperates with the marking |25 to indicate correct adjustment as will be described hereinafter.

This shock absorber functions in the following manner:

When the wheels of the vehicle strike an obstruction in theroadway over which the vehicle is being operated, the axle 2| secured to the frame 20 by vehicle springs |50 is thrust upwardly toward said frame, resulting in a movement oi' the piston 50 of the shock absorber toward the cylinder head member 26 for, as has been described heretofore, the piston rod 40 is connected with the frame 20 and the working cylinder tubular member 22 to the axle 2|. Fluid within the chamber beneath the piston will have pressure exerted thereon, which pressure when attaining a predetermined value, will flex the discvalve 41 against the effect of the resilient backing disc 45 from engagement with the annular ridges or valve seats 55 and 56 on the upper sur- `face of the piston. This permits a flow oi.' fluid from the chamber beneath the piston through passages 6| in the piston past the resilient disc valve 41, the restriction offered to this fluid flow by this valve being comparatively low. Due to the presence of the rod 40 in the chamber within the cylinder above the piston, not all the fluid displaced by the piston from the chamber 99 beneath it may be received by the upper chamber, and thus fluid pressure will be exerted within the tubular valve |03 through the side opening |06 therein against the bottom surface of the groove Vin the valve member ||0, urging it from engagement with the disc-valve |02 against the effect of springIIS and thus permitting 'a flow of fluid from the annular groove through the orifice presented between the valve ||0 and the lower surface of the disc-valve |02 through the cylinder head member 28 into the reservoir 25. Naturally some iluid will flow from the lower chamber. through the opening 12 in the'retainer 10 and through the piston passages 61, C-slot 49 in the valve 41 into the upper chamber. From this it can be seen that the fluid flow from the lower chamber into the upper chamber is substantially free. However, the fluid ow from the lower chamber into the reservoir past the valve device controlling the port |00 in the cyllnder head 28 is restricted to a greater degree.

Thus the shock absorber will oiler some restriction to the fluid flow from the chamber' beneath the piston and consequently itrwill oer a resistance to the approaching movements between the frame and axle of the vehicle.

'Ihe springs |60 after being compressed in a manner just described, will assume their normal position with a rebounding movement, causing a. separation between the axle and frame of the vehicle. During this separating movement the piston 60 of the shock absorber is moved in a direction away from the cylinder head member 26, exerting a pressure upon the fluid in the cylinder working chamber above the piston. 60. Fluid pressure will assist in urging the flexible disc-valve 41 upon its seats 66 and 66 to close piston passages 6|. However, due to the upward movement of the piston, fluid, from the upper chamber enters piston passages 61 through the C-shaped slot 46 in the flexible disc-valve 41 and from said piston passages 61 this fluid will enter "the annular groove 1| in the retainer 1I. From this annular groove 1| the fluid exits through the side opening 12, thence through the recess of the piston into the lower displacement chamber. The degree of restriction to the fluid flow through the side opening 12 is governed by the position of the sleeve valve 36 on the retainer 10. If this sleeve valve 66 has been adjusted so that the deepest portion 9| oi the sloping upper edge of the sleeve valve lies adjacent to the side opening 12, then the least restriction to fluid flow through this opening is obtained. However, if the sleeve valve 66 is adjusted so that a higher or more shallow portion of this slope lies adjacent the opening 12, naturally a portion of this sleeve valve will extend over a portion of the opening 12 and thus the fluid flow therethrough will be restricted to a greater degree. This restriction to fluid flow through opening' 12 will resist the downward movement of the piston and consequently cause the shock absorber to resist the approaching movement between the axle and frame of the vehicle. In this case also the presence of the piston rod in the kupper displacement chamber will becom'e effective, for

fluid displaced from the upperv chamber into the lower chamber, as has been described, will not completely till said lower chamber, consequently as the piston 60 is moved upwardly, an additional ow oi fluid into the chamber therebeneath is permitted by the lifting of valve |62 from its seat |0| against the effect of spring |09. this ilow coming from the reservoir 26 through the port |06 in the cylinder head member28 past the valve |02 into the chamber 09 beneath the piston 60, this supply being, as has been mentioned, in addition toithe flow transferred from the upper displacement chamber through the piston into the lower chamber.

In order to adjust the sleeve valve 66 so that it will more or less restrict the iluid flow through the side opening 12 in thegretainer 10, it must be rotated on the retainer 10. Normally the detent 92 holds the sleeve 66 against rotation upon the retainer 10. When it is desired to make such an adjustment, the piston of the shock absorber is moved downwardly into juxtaposition with the cylinder head member28` so that the tongue 93 will enter into and lockingly engage the notch II4 provided in the upper edge of the cylinder head member 28. Now the cylinder rod 40 may be rotated, causing rotation of the piston andthe retainer 10 relatively to the sleeve 66, for sleeve 86 cannot rotate while the tongue 63 of the als consequently the dust cover I0, for dust cover g and piston rod are both `secured to a common" member, are' rotated to the left or toward the word Firm", then the sloping edge 90 of the sleeve valve 85 will rise over the opening 12 in thel retainer 10 causing a lesser area of it to be exposed and therefore increasing the restriction to fluid ow therethrough. If on the contrary the rod and cover are rotated toward the right as regards Fig. 2, or toward the Soit position" then the lower or deeper part ci the sloping upper `surface 90 of the sleeve valve will approach the opening 12, causing a greater portion of it to be exposed and naturally reducing the restriction to the fluid iiow through this opening. 'I'he normal adjustment is indicated when the V-shaped notch |21 in the dust cover is in direct alignment with V-shaped mark |26 on the tube 23, this adjustment being determined when assembling the shock absorber. As the ducts or humps 98 of the duct 92 are moved from one notch to' the next adjacent notch formed by the ridges 80 on the retainer 10, the notch |21 on the dust cover will move from one mark of the indications |25 to the next adjacent one.

From the aforegoing itmay be seen that a fluid ow control device of the shock absorber. which device is in the interior of the shock absorber, may be adjusted exteriorly thereof without disassembling the device. By merely disconnecting the shock absorber from either the` the shock absorber to movements between the frame and axle oi the vehicle.

It may also be seen that inasmuch as iluid piston in both directions respectively. the approaching and separating movements oi.' the vehicle frame and axle may be varied to suit the desire oi the operator.-

While the embodiment oi the present invention as herein disclosed constitutes a preferredl form, it is to be'understood that other formsA might be provided, all coming within the scope lof the claims which follow.

What is claimed is as follows: 1 A hydraulic shock absorber comprising, in

combination, a cylinder having a head member;

a piston in said cylinder, provided with a fluid passage; a sleeve rotatably secured on the piston and adapted to throttle iluid flow through the 4piston passage; and Am'eans normally, yieldably maintaining the other oisaid passages open; I

control means adjustably carried by *the piston to for holding said means stationary while the' piston is rotated in the cylinder to alter the adjustment of said means relatively to said piston passages.

3. A hydraulic shock absorber comprising, in combination, a cylinder having a head member provided with a notch; a piston-in said cylinder.'

having fluid flow passages; a valve for controlling the flow of fluid through certain of said passages while maintaining the others open; a sleeve-valve rotatably carried by the piston and adapted to restrict the iiow of iluid through the said other piston passages; and means yieldably holding said sleeve-valve in adjusted positlonon the piston, said means being adapted to be moved into locking engagement with the cylinder head notch to hold the sleeve stationary while the piston is rotated to change the restriction to the 'flow of iluid through the piston by the sleevevalve.

. 4. AA hydraulic shock absorber comprising, in combination, a cylinder having a head member provided with a notch; a piston in said cylinder, having a plurality of iiuid flow passages; a iiexible disc-valve normally, yieldably closing certain of said passages while maintaining the other passages open; a sleeve-valve rotatably carried by the piston, said sleeve-valve having a sloping surface providing a restriction to the flow of iiuid through said other piston passages; and

a detent yieldably holding the sleeve-valve against rotation on the piston, said detent being adapted to be brought into locking engagement with the notch in the cylinder head when the piston is moved into juxtaposition with the said head member, thereby permitting the piston to be rotated relatively to the sleeve-valve to vary its restriction to the fluid ilow.

5. A hydraulic shock absorber of the directacting type, having concentrically arranged tubular members forming a iluid reservoir and a working cylinder; a head member i'or the cylinder, having a port providing communication with the reservoir; a valve device for said port controlling the flow of uid through said port in both directions; a vpiston in said cylinder, provided with an actuating rod, said piston having iiuid passages; a ilexible disc-valve yieldably, normally closing certain of said piston passages; a retainer threadedly secured to the piston rod and clamping the piston securely in position thereon, said retainer having an annular groove in communication with the other of said piston passages and an opening in its side wall, leading into said annular groove; a sleeve valve rotatably secured to the retainer and having means. for

` restricting the ilow of iluid from lthe opening in the retainer; and a detent engaging both the retainer and the sleeve valve, yieldably holding the latter in adjusted position on the retainer and adapted to engage the head member of the cylinder when the piston is moved into juxtaposition thereto for holding the sleeve-valve sta.-

tionary while the retainer and piston are rotated, thereby varying the restriction toiluid ow by said sleeve-valve.

6. A hydraulic shock absorber comprising, in combination, a cylinder having a head member provided with a notch; a pistonrin said cylinder ating the piston; a retainer threaded on/ the rod Cil and securing the'piston thereon,said retainer 'having an annular groove in the surface engaging the piston, certain piston passages .communicating with said groove, the retainer having an opening in its side wall leading into 'said groove; a sleeve rotatably supported by the retainer so that the one end of the sleeve extendsl `oversaid opening a portion of the surface of said sleeve stationary as the piston is rotated to they restriction of the retainer opening by said sleeve.

'7.y A hydraulic shock absorber, comprising in combination, acylinder having a head member; a piston in said cylinder provided witha uid passage; means for retricting the flow of fluid through said passage; and a flexible member yieldably securing the restricting means to the piston and having provisions adapted to be engageable with the cylinder head member for holding the restricting means stationary while the piston is rotated.

8. A hydraulic shock absorber comprising in combination, a cylinder having a head member; a piston vin said cylinder provided with a uid passage; a fluid flow restricting means for said passage, adjustably carried by the piston; and a exible Wedge interposed between the restricting means and the piston, urging the said means into proper position longitudinally relatively to the piston passage and yieldably holding said restricting means non-rotatable on said piston, said flexible wedge having a portion adaptable to be moved into engagement with the cylinder head to hold said restricting means immovable while the piston is rotated relatively to the cylinder head.v

9. A hydraulic shock absorber comprising, in combination, a ,cylinder head having a head member provided with a notch; a piston in said cylinder having a fluid passage therethrough; a throttle for said fluid passage, and a resilient wedge for Ayieldably locking the throttle against rotation relatively to the piston, and having an extension adapted to be moved into locking engagement with the notch of the cylinder head to hold the throttle against rotation while the piston is being rotated relatively to the cylinder.

f EDWIN F. ROSSMAN.

FREDERICK D. FUNSTON. 

